/*
 * [New BSD License]
 * Copyright (c) 2011-2012, Brackit Project Team <info@brackit.org>  
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Brackit Project Team nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.brackit.xquery.function.fn;

import org.brackit.xquery.ErrorCode;
import org.brackit.xquery.QueryContext;
import org.brackit.xquery.QueryException;
import org.brackit.xquery.atomic.QNm;
import org.brackit.xquery.function.AbstractFunction;
import org.brackit.xquery.module.StaticContext;
import org.brackit.xquery.xdm.Item;
import org.brackit.xquery.xdm.Iter;
import org.brackit.xquery.xdm.Sequence;
import org.brackit.xquery.xdm.Signature;
import org.brackit.xquery.xdm.type.Cardinality;

/**
 * 
 * @author Sebastian Baechle
 * 
 */
public class CardinalityTest extends AbstractFunction {
	private final Cardinality cardinality;

	public CardinalityTest(QNm name, Signature signature,
			Cardinality cardinality) {
		super(name, signature, true);
		this.cardinality = cardinality;
	}

	@Override
	public Sequence execute(StaticContext sctx, QueryContext ctx, Sequence[] args)
			throws QueryException {
		if (cardinality == Cardinality.One) {
			return exactlyOnce(args);
		} else if (cardinality == Cardinality.OneOrMany) {
			return oneOrMore(args);
		} else if (cardinality == Cardinality.ZeroOrOne) {
			return zeroOrOne(args);
		} else {
			throw new QueryException(ErrorCode.BIT_DYN_RT_ILLEGAL_STATE_ERROR,
					"Unsupported cardinality test: %s", cardinality);
		}
	}

	private Sequence zeroOrOne(Sequence[] args) throws QueryException {
		Sequence s = args[0];
		if ((s != null) && (!(s instanceof Item))) {
			Iter it = s.iterate();
			try {
				if (((s = it.next()) != null) && (it.next() != null)) {
					throw new QueryException(ErrorCode.ERR_ZERO_OR_ONE_FAILED,
							"fn:zero-or-one called with a sequence containing more than one item");
				}
			} finally {
				it.close();
			}
		}
		return s;
	}

	private Sequence oneOrMore(Sequence[] args) throws QueryException {
		Sequence s = args[0];
		if (s == null) {
			throw new QueryException(ErrorCode.ERR_ONE_OR_MORE_FAILED,
					"fn:one-or-more called with an empty sequence");
		} else if (!(s instanceof Item)) {
			Iter it = s.iterate();
			try {
				if (it.next() == null) {
					throw new QueryException(ErrorCode.ERR_ONE_OR_MORE_FAILED,
							"fn:one-or-more called with an empty sequence");
				}
			} finally {
				it.close();
			}
		}
		return s;
	}

	private Sequence exactlyOnce(Sequence[] args) throws QueryException {
		Sequence s = args[0];
		if (s == null) {
			throw new QueryException(ErrorCode.ERR_EXACTLY_ONCE_FAILED,
					"fn:exactly-one called with an empty sequence");
		} else if (!(s instanceof Item)) {
			Iter it = s.iterate();
			try {
				if ((s = it.next()) == null) {
					throw new QueryException(ErrorCode.ERR_EXACTLY_ONCE_FAILED,
							"fn:exactly-one called with an empty sequence");
				}
				if (it.next() != null) {
					throw new QueryException(ErrorCode.ERR_EXACTLY_ONCE_FAILED,
							"fn:exactly-one called with a sequence containing more than one item");
				}
			} finally {
				it.close();
			}
		}
		return s;
	}
}